A device for dispensing flowable substances, having the features recited in the preamble of claim 1, is known from EP 0 492 413 A1. There is provided a shell-shaped receptacle for receiving two cartridges in parallel, each cartridge having, at its rear end, a dispensing piston and, at its front end, an opening to be coupled to a rear entry opening of a mixer provided on the device. During dispensing, both pistons are synchronously advanced by an electrical motor which also drives a rotor within the mixer.
The advancing speed of the pistons and, possibly, also the driving speed of the mixer rotor can depend upon the properties of the substances contained in the cartridges, to such as viscosity or sensitivity to mechanical forces. The proper dispensing parameters are to be selected by the operator. Setting unsuitable parameters may lead to undesired changes of the substance being dispensed or damages to the device.
Some substances have properties that change over time and are therefore to be used prior to an expiry date determined by the producer. This is particularly true with components which react with each other and are mixed together for producing a ready-to-use substance. If the operator fails to pay attention to the expiry date, the substance dispensed from the device may be unusable or at least deteriorated in its properties.
Finally, it is essential for each cartridge to be properly inserted into the receptacle of the device. If this is not done, entry of the piston into the cartridge and/or engagement of the mixer shaft in the mixer is not properly ensured, which may cause damage to the device, lead to unmixed substances being dispensed, or result in leakage. Again, one relies on the operator to insert the cartridges properly.
DE 39 19 105 A1 discloses a gluing machine in which cartridges are filled with adhesive components in a predetermined mixing ratio. A visible marking tells the operator whether the machine has been properly filled in accordance with the mixing ratio. There is also mention of a xe2x80x9cpneumaticxe2x80x9d encoding and inhibition of the gluing machine if wrong cartridges are inserted.
It is the object of the invention to prevent such a dispensing device from being improperly handled, specifically from having a container improperly inserted or an unsuited container being inserted, possibly also an unsuited mixer being used.
The invention is characterized in claim 1 provides a solution to this object. According to claim 1, a marking provided on the container and its detection by means provided in the device make sure that the emptying mechanism of the device functions only if the marking has been recognized as admissible, and possibly operates in response to the contents of the marking. The marking may contain information concerning the properties of the container content, its durability, the producer, and other data. Since the marking and the detecting means must be related to each other, it becomes possible to make sure that the marking is recognized as valid only if the container is in a predetermined position within the receptacle of the device.
Preferred embodiments of the marking and of the detecting means cooperating therewith are recited in claims 2 to 6.
The embodiments of the invention set forth in claims 7, 8 and 16 relate to a preferred location of the marking and detecting means on the container and on the device, respectively.
It is of particular advantage to use the marking for establishing not only the proper position of the container but also the proper operation of the device, as in the embodiment of the invention according to claims 9 and 10.
The embodiment of claim 11 is specifically related to the detection of the internal pressure of the container which, under certain conditions, may become excessive during dispensing. To this end, it is specifically a deformation of the container cap that is detected, which deformation may occur if it is attempted to dispense improper or too old and taut pastes whereby a certain maximum dispensing force is exceeded. It thus becomes possible to avoid damage to the dispensing device, contamination of the device due to breakage of a container, or other risks. There is thus not only detection as to whether a container suited for the device has been properly inserted; overload conditions during dispensing are also prevented. This avoids the need for an expensive overload clutch, as is provided with some prior-art devices.
Embodiments of the marking and detecting means which are advantageous for this use are recited in claims 12 to 15.
The embodiment of the invention according to claims 17 and 18 is of advantage in that it ensures the use of a proper mixture in a mixing and dispensing device for mixtures of two or more components.
The feature of claim 19 is advantageous in that certain information contained in the marking, such as the expiry date, are immediately recognizable to the user.